1. Field of the Invention
This invention relates to apparatus and method for cooling the brain, and in particular to apparatus and method for inducing hypothermia throughout the tissues of the brain.
2. Description Relative to the Prior Art
It is well known in the medical art that depriving the brain of oxygen for even a short period of time results in irreversible damage to the brain tissue. Such deprivation occurs during stroke, respiratory arrest, cardiac arrest, trauma and other severe bodily disturbances that slow or otherwise hinder the flow of oxygenated blood to the brain. However, it is also known that lowering the temperature of the brain (hypothermia) slows its metabolic activity, and reduces the chance of tissue damage when the oxygen supply is diminished.
At present, operative neurosurgery and cardiac surgery is done in many cases using hypothermia for the specific purposes of maintaining cerebral and cardiac function. In an operating room, this requires use of a cooling module in conjunction with heart/lung bypass techniques by which the patient's blood, and resultantly the patient's brain tissue, is cooled. This widespread ability to rapidly lower brain temperature by as little as four or five degrees can make an enormous difference in preservation of function. However, out in the field, when medical emergencies occur, brain cooling must quickly and expeditiously take place without access to the sophisticated equipment available in the hospital operating room. A portable brain cooling apparatus usable in the field is described in U.S. Pat. No. 5,261,399, issued in the names of Klatz et al. For use on an injured or disabled patient, the patent discloses a helmet and back plate containing cavities in which a coolant flows to cool the brain by means of heat conduction through the skull and upper spinal column.